The present invention relates to a gas insulated circuit breaker system with a resistor and a gas insulated circuit breaker monitoring method and, more particularly, to a technique that takes temperature rise of the resistor into consideration so as to improve operation performance of a gas insulated circuit breaker with resistor.
In a gas insulated circuit breaker used in an electric power substation, a resistor/contact connected member obtained by serially connecting a resistor contact and a resistor is connected in parallel to a main contact in order to suppress a surge voltage generated at the contact closing/opening time. At the contact closing time, the resistor contact is closed before the closing of the main contact, and at the contact opening time, the resister contact is opened after the opening of the main contact. At the operating time, a large energy is injected to the resistor to heat the resistor up to 200° C. to 300° C. Thus, when the resistor has a large resistance value in the high temperature range of 200° C. to 300° C., an over-current may flow through the resistor. If the resistor breaks down due to the flowing of over-current, a thermo-runaway may occur (refer to, e.g., Japanese Patent Application Laid-open Publication No. 05-041302, the entire content of which is incorporated herein by reference).
The above mentioned conventional gas insulated circuit breaker with resistor needs to wait, after breaking a fault current, until the temperature of the resistor is lowered to a level at which the resistor does not break down due to a temperature rise caused by the subsequent operation. Since the conventional gas insulated circuit breaker does not have a means for detecting the temperature of the resistor, it needs to wait for a certain period of time.